This is great news. Many applications stopped supporting PHP4 in 2008, and the last release of MYSQL 4 was in March of 2005. Supporting legacy tech isn't a bad thing, but at some point we have to stop pulling plows with mules.
Hacking WordPress is frustrating because it's so poorly engineered, and that won't change for the foreseeable future. It's a sprawling mess of Spaghetti code that's indecipherable without the WordPress Codex and Google Search. But despite all my rage, clients keep asking for it, and it keeps paying my bills.
I think you struck on an important point. For clients Wordpress is a godsend. If you quit contracting or the client needs to change developers for one of a thousand reasons there's a massive pool of talent that can step right in and make adjustments. I've taken over Wordpress sites and the learning curve is almost flat (save a few weird plugins). Anyways, it's a whole lot better of a situation for clients, developers and productivity in general than the days when everyone had a custom framework that solved the same basic CMS issue.
Is there another CMS that has the same featureset and the same extensibility? I've tried a few, but keep coming back to Wordpress, even though it is annoying and a resource hog. It's too easy to extend, and it has most of the stuff I need built in to the core (as of 3.0 at least). I wish there were an alternative platform that ran on Python and Sqlite with the same polish in terms of features and ease-of-use, but I haven't found one yet (correct me if I'm wrong!)
I am not one of the biggest fans of Wordpress but after working with Wordpress 3 I was surprised how easy it was to fully develop a theme. The dynamic menus for me where one of the biggest time-savers for me. I've had so many problems with clients wanting different stuff on the main menu.
I sub-contract quick Wordpress jobs, code on my pet-projects during my free time and work on my day-job. So any improvements on Wordpress affects a lot of my routine - I can do more stuff :D
